Opencv learning notes-day9 opencv's own color table operation (colormap coloraptypes enumeration data types and applycolormap() pseudo color function)

OpenCV With color table operation

use OpenCV Bring your own color table to change the image color

function

1. colormap（ Chromaticity diagram ）

OpenCV The definition of colormap（ Chromaticity diagram ）, Can be applied to grayscale images , Using functions applycolormap Generate pseudo color image .

// Definition ColormapTypes  Enumerate data types 
enum ColormapTypes
{
    
    COLORMAP_AUTUMN = 0, //!< ![autumn](pics/colormaps/colorscale_autumn.jpg)
    COLORMAP_BONE = 1, //!< ![bone](pics/colormaps/colorscale_bone.jpg)
    COLORMAP_JET = 2, //!< ![jet](pics/colormaps/colorscale_jet.jpg)
    COLORMAP_WINTER = 3, //!< ![winter](pics/colormaps/colorscale_winter.jpg)
    COLORMAP_RAINBOW = 4, //!< ![rainbow](pics/colormaps/colorscale_rainbow.jpg)
    COLORMAP_OCEAN = 5, //!< ![ocean](pics/colormaps/colorscale_ocean.jpg)
    COLORMAP_SUMMER = 6, //!< ![summer](pics/colormaps/colorscale_summer.jpg)
    COLORMAP_SPRING = 7, //!< ![spring](pics/colormaps/colorscale_spring.jpg)
    COLORMAP_COOL = 8, //!< ![cool](pics/colormaps/colorscale_cool.jpg)
    COLORMAP_HSV = 9, //!< ![HSV](pics/colormaps/colorscale_hsv.jpg)
    COLORMAP_PINK = 10, //!< ![pink](pics/colormaps/colorscale_pink.jpg)
    COLORMAP_HOT = 11, //!< ![hot](pics/colormaps/colorscale_hot.jpg)
    COLORMAP_PARULA = 12, //!< ![parula](pics/colormaps/colorscale_parula.jpg)
    COLORMAP_MAGMA = 13, //!< ![magma](pics/colormaps/colorscale_magma.jpg)
    COLORMAP_INFERNO = 14, //!< ![inferno](pics/colormaps/colorscale_inferno.jpg)
    COLORMAP_PLASMA = 15, //!< ![plasma](pics/colormaps/colorscale_plasma.jpg)
    COLORMAP_VIRIDIS = 16, //!< ![viridis](pics/colormaps/colorscale_viridis.jpg)
    COLORMAP_CIVIDIS = 17, //!< ![cividis](pics/colormaps/colorscale_cividis.jpg)
    COLORMAP_TWILIGHT = 18, //!< ![twilight](pics/colormaps/colorscale_twilight.jpg)
    COLORMAP_TWILIGHT_SHIFTED = 19 //!< ![twilight shifted](pics/colormaps/colorscale_twilight_shifted.jpg)
};

Quote an example

int colormap[] = {
    
		COLORMAP_AUTUMN,
		COLORMAP_BONE,
		COLORMAP_JET,
		COLORMAP_WINTER,
		COLORMAP_RAINBOW,
		COLORMAP_OCEAN,
		COLORMAP_SUMMER,
		COLORMAP_SPRING,
		COLORMAP_COOL,
		COLORMAP_PINK,
		COLORMAP_HOT,
		COLORMAP_PARULA,
		COLORMAP_MAGMA,
		COLORMAP_INFERNO,
		COLORMAP_PLASMA,
		COLORMAP_VIRIDIS,
		COLORMAP_CIVIDIS,
		COLORMAP_TWILIGHT,
		COLORMAP_TWILIGHT_SHIFTED,
	};

2. applyColorMap（） Pseudo color function

// Definition 
CV_EXPORTS_W void applyColorMap(InputArray src, OutputArray dst, int colormap);

Parameters	explain
src	The source image （ Grayscale or color chart （CV_8UC1 or CV_8UC3））
dst	The result image after color mapping on the source image
colormap	Color map code value provided （ See ：ColormapTypes Enumerate data types ）

example

applyColorMap(image,dst,colormap[index%20]);//index%20  Guarantee colorMap The parameters inside are colormap[0-19] Between , To facilitate the selection of members in enumeration data types 

Code

#pragma once

#include <opencv2\highgui.hpp>

#include <opencv2\imgproc.hpp>

using namespace cv;
// Defining classes 
class QuickDemo{
    
public:
	void colorSpace_Demo(Mat &image);// Color space conversion function 2021-12-24
	void mat_creation_demo(Mat &image);//Mat Object and creation 2021-12-27
	void pixel_vist_Demo(Mat &image);// Read and write operation of image pixels 2022-1-3
	void operators_demo(Mat &image);// Arithmetic operation of image pixels 2022-1-4
	void tracking_bar_demo(Mat &image);// Scroll bar operation demonstration 2022-1-7
	void key_demo(Mat &image);// Keyboard response operation 2022-1-12
	void color_style_demo(Mat &image);//OpenCV With color table operation 2022-1-12
};

QuickDemo.cpp

#include <opencv2\highgui.hpp>

#include <opencv2\imgproc.hpp>

#include<quickopencv.h>

#include <iostream>
void QuickDemo::color_style_demo(Mat &image)
{
    
	int colormap[] = {
    
		COLORMAP_AUTUMN,
		COLORMAP_BONE,
		COLORMAP_JET,
		COLORMAP_WINTER,
		COLORMAP_RAINBOW,
		COLORMAP_OCEAN,
		COLORMAP_SUMMER,
		COLORMAP_SPRING,
		COLORMAP_COOL,
		COLORMAP_PINK,
		COLORMAP_HOT,
		COLORMAP_PARULA,
		COLORMAP_MAGMA,
		COLORMAP_INFERNO,
		COLORMAP_PLASMA,
		COLORMAP_VIRIDIS,
		COLORMAP_CIVIDIS,
		COLORMAP_TWILIGHT,
		COLORMAP_TWILIGHT_SHIFTED,
		COLORMAP_HSV,
	};
	Mat dst;
	int index = 0;
	while (true)
	{
    
		int c = waitKey(1000);
		if (c == 27){
    
			break;
		}
		applyColorMap(image,dst,colormap[index%20]);//index%19  Guarantee colorMap The parameters inside are 0-18 Between 
		index++;
		imshow(" Color style ", dst);
	}
}

OpencvTest.cpp

#include <iostream>
#include <opencv2\highgui.hpp>
#include <opencv2\imgproc.hpp>
#include<quickopencv.h>

using namespace cv;
using namespace std;


int main()
{
    
	Mat scr = imread("...\\image\\1.jpg");// Open a picture 
	if (!scr.data == 1)// Sentenced to empty 
		return -1;
	namedWindow(" window 1", WINDOW_NORMAL);// establish  WINDOW_FREERATIO window 
	imshow(" window 1",scr);// Show in the created window 
	QuickDemo qd;
	qd.color_style_demo(scr);
	waitKey(0);
	return 0;
}

According to the effect

20 Color intervals 1 Seconds in sequence , Press ESC Key exit program